Unfortunately SR 4 had a period (both during teh FanPro days and later during the earlier CGL days) when they hit a few production snags. Shadowrun 4 has been in print for over 6 years now (6 1/2 next month), but the Storyline has only progressed 4 years this far. The most recent release, Corporate intrigue, has an "in game" date of December 2073, so we're just now entering 2074.
Missions, on the other hand, is in a wierder place.
Season 1 and 2 were done as fan-produced projects. Season 1 was still 3rd edition, so it falls into 2064 at the latest. There are no exact dates for it. Season 2 is 4th edition, which starts in 2070 and runs through 2071 (It was 26 or so Missions).
Season 3 was loosely 2071-2 (There were a number of production delays with Season 3, partly related to the delays with the main line)
Season 4 is assumed to start at the end of 2071. December to be exact. The first two Missions that really start nailing the Seattle Missions timeline into place are actually two Convention Missions, CMP 2010-02 Copycat Killer and CMP 2010-03 Ashes. (CMP 2010-02 is available as a free bonus when you buy SRM 04-05: on a Silver Platter. Ashes will be out soonish.) Both of these specifically take place after Knight Errant takes over the city contract for Seattle, and they lay the groundwork for some of what we decided to do with Season 4. A handout included in CMP 2010-02 is dated February of 2072, and is at least 3 months old when the players receive it.
For storyline purposes, I assume that 2010-02 takes place in May, and 2010-03 takes place in June.
SRM 04-00: Back in Business starts in December 2072, though tehre's nothing in the book to really date it, other than a reference to the events of 2010-02 and 2010-03 as being "last summer".
From tehre, I'm assuming one month per Mission, for teh purposes of story. Anytime the Missions refer back to earlier events, they sill say "It happened 2 months ago" if it was 2 Missions ago. The final Mission in the Buried underground plotline, which deals with some city politics and a vote regarding teh fate of the Underground happens in November 2073, and will happen in SRM 04-11. So I'm adhering to that timeline, even though we're currently behind the main gameline a little bit.
Due to production snafus (Mainly, we have too few people and too many products came out this year, and Missions often got pushed back), we have not been able to maintain the 1 Mission per Month schedule I wanted to maintain for the main SRM line (We did also produce 8 Convention Missions this year), and ended up averaging 1 Mission every 2 months. I'm hoping to force the schedule back on track this year. 04-06 is on deck, just awaiting some final approvals, and 04-07 is approaching the finish line, for example.
Anyway, probably more info than you were looking for
I do taht when i talk Missions.
Short answer:
Season 1 - 2064
Season 2 - 2070-2071
Season 3 - 2071-2072
Season 4 - 2073-2074*
(There are more Season 4 Missions planned after 04-12, and they will roll into 2074 then)
Bull